mlua 0.10.0 panicking randomly with "internal error: 1 too many stack values popped"

[sxyazi]

Hi! I'm upgrading the mlua version of Yazi from 0.9.9 to 0.10.0. It compiles fine now, but I'm getting random panics at runtime:

The application panicked (crashed).
  mlua internal error: 1 too many stack values popped (this is a bug, please file an issue)
in rust:library/core/src/ptr/mod.rs, line 574
thread: tokio-runtime-worker

Here's the stack trace:

  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/mlua-0.10.0/src/macros.rs", line 27, in <mlua::util::StackGuard as core::ops::drop::Drop>::drop
    panic!(bug_msg!($msg), $($arg),+)
  File "rust:library/core/src/ptr/mod.rs", line 574, in core::ptr::drop_in_place<mlua::util::StackGuard>
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/mlua-0.10.0/src/state/raw.rs", line 987, in mlua::state::raw::RawLua::push_userdata_metatable
    }
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/mlua-0.10.0/src/state/raw.rs", line 818, in mlua::state::raw::RawLua::create_userdata_metatable
    self.push_userdata_metatable(registry)?;
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/mlua-0.10.0/src/state/raw.rs", line 758, in mlua::state::raw::RawLua::make_userdata::{{closure}}
    self.create_userdata_metatable(registry)
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/mlua-0.10.0/src/state/raw.rs", line 790, in mlua::state::raw::RawLua::make_userdata_with_metatable
    ffi::lua_rawgeti(state, ffi::LUA_REGISTRYINDEX, get_metatable_id()?);
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/mlua-0.10.0/src/state/raw.rs", line 747, in mlua::state::raw::RawLua::make_userdata
    self.make_userdata_with_metatable(data, || {
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/mlua-0.10.0/src/state.rs", line 1255, in mlua::state::Lua::create_userdata
    unsafe { self.lock().make_userdata(UserDataStorage::new(data)) }
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/mlua-0.10.0/src/conversion.rs", line 233, in mlua::conversion::<impl mlua::traits::IntoLua for T>::into_lua
    Ok(Value::UserData(lua.create_userdata(self)?))
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/mlua-0.10.0/src/traits.rs", line 28, in mlua::traits::IntoLua::push_into_stack
    lua.push_value(&self.into_lua(lua.lua())?)
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/mlua-0.10.0/src/table.rs", line 256, in mlua::table::Table::raw_set
    value.push_into_stack(&lua)?;
  File "/Users/alice/Desktop/yazi/yazi-plugin/src/isolate/peek.rs", line 49, in yazi_plugin::isolate::peek::peek::{{closure}}::{{closure}}
    plugin.raw_set("window", Window::default())?;
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/macros/select.rs", line 557, in yazi_plugin::isolate::peek::peek::{{closure}}::{{closure}}::{{closure}}
    let out = match Future::poll(fut, cx) {
  File "rust:library/core/src/future/poll_fn.rs", line 151, in <core::future::poll_fn::PollFn<F> as core::future::future::Future>::poll
  File "/Users/alice/Desktop/yazi/yazi-plugin/src/isolate/peek.rs", line 55, in yazi_plugin::isolate::peek::peek::{{closure}}::{{closure}}
    select! {
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/park.rs", line 281, in tokio::runtime::park::CachedParkThread::block_on::{{closure}}
    if let Ready(v) = crate::runtime::coop::budget(|| f.as_mut().poll(&mut cx)) {
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/coop.rs", line 107, in tokio::runtime::coop::with_budget
    f()
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/coop.rs", line 73, in tokio::runtime::coop::budget
    with_budget(Budget::initial(), f)
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/park.rs", line 281, in tokio::runtime::park::CachedParkThread::block_on
    if let Ready(v) = crate::runtime::coop::budget(|| f.as_mut().poll(&mut cx)) {
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/context/blocking.rs", line 66, in tokio::runtime::context::blocking::BlockingRegionGuard::block_on
    park.block_on(f)
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/handle.rs", line 327, in tokio::runtime::handle::Handle::block_on_inner::{{closure}}
    blocking.block_on(future).expect("failed to park thread")
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/context/runtime.rs", line 65, in tokio::runtime::context::runtime::enter_runtime
    return f(&mut guard.blocking);
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/handle.rs", line 326, in tokio::runtime::handle::Handle::block_on_inner
    context::enter_runtime(&self.inner, true, |blocking| {
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/handle.rs", line 305, in tokio::runtime::handle::Handle::block_on
    self.block_on_inner(future, SpawnMeta::new_unnamed(fut_size))
  File "/Users/alice/Desktop/yazi/yazi-plugin/src/isolate/peek.rs", line 54, in yazi_plugin::isolate::peek::peek::{{closure}}
    let result = Handle::current().block_on(async {
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/blocking/task.rs", line 42, in <tokio::runtime::blocking::task::BlockingTask<T> as core::future::future::Future>::poll
    Poll::Ready(func())
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/task/core.rs", line 331, in tokio::runtime::task::core::Core<T,S>::poll::{{closure}}
    future.poll(&mut cx)
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/loom/std/unsafe_cell.rs", line 16, in tokio::loom::std::unsafe_cell::UnsafeCell<T>::with_mut
    f(self.0.get())
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/task/core.rs", line 320, in tokio::runtime::task::core::Core<T,S>::poll
    self.stage.stage.with_mut(|ptr| {
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/task/harness.rs", line 499, in tokio::runtime::task::harness::poll_future::{{closure}}
    let res = guard.core.poll(cx);
  File "rust:library/core/src/panic/unwind_safe.rs", line 272, in <core::panic::unwind_safe::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
  File "rust:library/std/src/panicking.rs", line 557, in std::panicking::try::do_call
  File "<unknown>", line 0, in ___rust_try
  File "rust:library/std/src/panicking.rs", line 520, in std::panicking::try
  File "rust:library/std/src/panic.rs", line 348, in std::panic::catch_unwind
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/task/harness.rs", line 487, in tokio::runtime::task::harness::poll_future
    let output = panic::catch_unwind(panic::AssertUnwindSafe(|| {
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/task/harness.rs", line 209, in tokio::runtime::task::harness::Harness<T,S>::poll_inner
    let res = poll_future(self.core(), cx);
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/task/harness.rs", line 154, in tokio::runtime::task::harness::Harness<T,S>::poll
    match self.poll_inner() {
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/task/raw.rs", line 271, in tokio::runtime::task::raw::poll
    harness.poll();
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/task/raw.rs", line 201, in tokio::runtime::task::raw::RawTask::poll
    unsafe { (vtable.poll)(self.ptr) }
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/task/mod.rs", line 472, in tokio::runtime::task::UnownedTask<S>::run
    raw.poll();
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/blocking/pool.rs", line 161, in tokio::runtime::blocking::pool::Task::run
    self.task.run();
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/blocking/pool.rs", line 511, in tokio::runtime::blocking::pool::Inner::run
    task.run();
  File "/Users/alice/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.41.0/src/runtime/blocking/pool.rs", line 469, in tokio::runtime::blocking::pool::Spawner::spawn_thread::{{closure}}
    rt.inner.blocking_spawner().inner.run(id);
  File "rust:library/std/src/sys/backtrace.rs", line 154, in std::sys::backtrace::__rust_begin_short_backtrace
  File "rust:library/std/src/thread/mod.rs", line 522, in std::thread::Builder::spawn_unchecked_::{{closure}}::{{closure}}
  File "rust:library/core/src/panic/unwind_safe.rs", line 272, in <core::panic::unwind_safe::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
  File "rust:library/std/src/panicking.rs", line 557, in std::panicking::try::do_call
  File "<unknown>", line 0, in ___rust_try
  File "rust:library/std/src/panicking.rs", line 520, in std::panicking::try
  File "rust:library/std/src/panic.rs", line 348, in std::panic::catch_unwind
  File "rust:library/std/src/thread/mod.rs", line 521, in std::thread::Builder::spawn_unchecked_::{{closure}}
  File "rust:library/core/src/ops/function.rs", line 250, in core::ops::function::FnOnce::call_once{{vtable.shim}}
  File "rust:library/alloc/src/boxed.rs", line 2453, in <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
  File "rust:library/alloc/src/boxed.rs", line 2453, in <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
  File "rust:library/std/src/sys/pal/unix/thread.rs", line 105, in std::sys::pal::unix::thread::Thread::new::thread_start
  File "<unknown>", line 0, in __pthread_joiner_wake

In my case, I'm using tokio::task::spawn_blocking() to concurrently create multiple Lua 5.4 instances to do some time-consuming operations, and this error occurs when setting userdata for a table:

plugin.raw_set("window", Window::default())?;

The Window struct is a normal structure that implements UserData:

#[derive(Debug, Clone, Copy, FromLua)]
pub struct Window {
	pub rows:   u16,
	pub cols:   u16,
	pub width:  u16,
	pub height: u16,
}

impl UserData for Window {
	fn add_fields<F: mlua::UserDataFields<Self>>(fields: &mut F) {
		fields.add_field_method_get("rows", |_, me| Ok(me.rows));
		fields.add_field_method_get("cols", |_, me| Ok(me.cols));
		fields.add_field_method_get("width", |_, me| Ok(me.width));
		fields.add_field_method_get("height", |_, me| Ok(me.height));
	}
}

This issue comes up really randomly, and I've tried for a long time to create a minimal reproduction for it, but no luck :(

I think it might be related to set_hook(), after I commented out the following code no more panicking again:

lua.set_hook(
  HookTriggers::new().on_calls().on_returns().every_nth_instruction(2000),
  move |_, _| {
    if ct1.is_cancelled() {
      Err("Peek task cancelled".into_lua_err())
    } else {
      Ok(VmState::Continue)
    }
  },
);

[khvzak]

Thanks for the report! I pushed a fix, could you try the latest main branch?

[sxyazi]

I can confirm the main branch fixed it - I've been running it for a while and haven't encountered any more panics. Thank you so much!